Uplink feedback methods for operating with a large number of carriers

Abstract

A wireless transmit/receive unit (WTRU) may receive one or more physical downlink shared channel (PDSCH) transmissions and each PDSCH transmission may be associated with downlink control information (DCI) and a group of PDSCH transmissions. Further, the WTRU may determine a first group or a second group based on an indication received in DCI associated with at least one of the PDSCH transmissions. Then, the WTRU may generate hybrid automatic repeat request (HARQ)-acknowledgment (ACK) feedback for data received in one or more PDSCH transmissions associated with the determined group. Moreover, the WTRU may transmit the HARQ-ACK feedback. In an example, the DCI which includes the indication may schedule a plurality of PDSCH transmissions included in the determined group. In another example, the DCI which includes the indication may further include a first codepoint mapped to the first group or a second codepoint mapped to the second group.

What is claimed: 
     
       1. A wireless transmit receive unit (WTRU) comprising a processor and a memory, the processor and the memory configured to:
 receive a first downlink control information (DCI), the first DCI comprising scheduling information for a first downlink transmission, wherein the first DCI comprises an indication that hybrid automatic repeat request (HARQ) feedback for the first downlink transmission is not expected in response to the first DCI; 
 receive a second DCI, the second DCI comprising a request to transmit the HARQ feedback for the first downlink transmission; and 
 transmit the HARQ feedback for the first downlink transmission scheduled by the first DCI based on the request comprised in the second DCI. 
 
     
     
       2. The WTRU of  claim 1 , wherein the first downlink transmission comprise a first physical downlink shared channel (PDSCH) transmission. 
     
     
       3. The WTRU of  claim 1 , wherein the second DCI indicates scheduling information for transmission of the HARQ feedback for the first transmission scheduled by the first DCI. 
     
     
       4. The WTRU of  claim 1 , wherein the first DCI is received via a first physical downlink control channel (PDCCH) transmission, and the second DCI is received via a second PDCCH transmission. 
     
     
       5. The WTRU of  claim 1 , wherein the second DCI comprises scheduling information for a second downlink transmission. 
     
     
       6. The WTRU of  claim 5 , wherein HARQ feedback for the second downlink transmission is transmitted with the HARQ feedback for the first downlink transmission. 
     
     
       7. The WTRU of  claim 1 , wherein the indication that the HARQ feedback for the first transmission is not expected in response to the first DCI comprises a codepoint of the first DCI being set to a specific value. 
     
     
       8. The WTRU of  claim 1 , wherein the second DCI does not include scheduling information for a physical downlink shared channel (PDSCH) transmission. 
     
     
       9. A method performed by a wireless transmit receive unit (WTRU), the method comprising:
 receiving a first downlink control information (DCI), the first DCI comprising scheduling information for a first downlink transmission, wherein the first DCI comprises an indication that hybrid automatic repeat request (HARQ) feedback for the first downlink transmission is not expected in response to the first DCI; 
 receiving a second DCI, the second DCI comprising a request to transmit the HARQ feedback for the first downlink transmission; and 
 transmitting the HARQ feedback for the first downlink transmission scheduled by the first DCI based on the request comprised in the second DCI. 
 
     
     
       10. The method of  claim 9 , wherein the first downlink transmission comprise a first physical downlink shared channel (PDSCH) transmission. 
     
     
       11. The method of  claim 9 , wherein the second DCI indicates scheduling information for transmission of the HARQ feedback for the first transmission scheduled by the first DCI. 
     
     
       12. The method of  claim 9 , wherein the first DCI is received via a first physical downlink control channel (PDCCH) transmission, and the second DCI is received via a second PDCCH transmission. 
     
     
       13. The method of  claim 9 , wherein the second DCI comprises scheduling information for a second downlink transmission. 
     
     
       14. The method of  claim 13 , wherein HARQ feedback for the second downlink transmissions is transmitted with the HARQ feedback for the first downlink transmission. 
     
     
       15. The method of  claim 9 , wherein the indication that the HARQ feedback for the first transmission is not expected in response to the first DCI comprises a codepoint the first DCI being set to a specific value. 
     
     
       16. The method of  claim 9 , wherein the second DCI does not include scheduling information for a physical downlink shared channel (PDSCH) transmission. 
     
     
       17. A base station comprising a processor and a memory, the processor and the memory configured to:
 transmit a first downlink control information (DCI), the first DCI comprising scheduling information for a first downlink transmission, wherein the first DCI comprises an indication that hybrid automatic repeat request (HARQ) feedback for the first downlink transmission is not expected in response to the first DCI; 
 transmit a second DCI, the second DCI comprising a request to transmit the HARQ feedback for the first downlink transmission; and 
 receive the HARQ feedback for the first downlink transmission scheduled by the first DCI based on the request comprised in the second DCI.